The present invention is intended particularly for use in producing pouches of the type described in detail in application Ser. No. 231,288, filed Mar. 2, 1972, and for filling and sealing such pouches. However, while it is specially intended for that purpose, and the detailed description which follows is in many particulars related to that purpose, it will be recognized that various features of the invention have more general application to other containers.
In the above-mentioned copending application, a variety of pouches are formed of opposed pairs of thermoplastic strips heat-sealed together along seams which, to best advantage, form the edge of the pouch. Each pouch has a fluid-discharge spout that is specially shaped to enable a releasable and reclosable seal to form across the spout. The kind of seam formed is such as to dispose the walls of the spouts essentially face-to-face when the pouch is empty, to promote formation of secure releasable seals. The pouch can be filled via the fluid-discharge spout or via a separate spout. Thereafter the opening used for filling the pouch is closed by a seam.
Methods and machines that use plastic films in forming and filling pouches of which I am aware are poorly suited to using the spouts of pouches as filling ports; they seem poorly suited to forming pouches having spouts whose walls are essentially face-to-face when empty for developing the releasable seals of application, Ser. No. 231,288, especially where the spouch is to be cut out along the seam; and they are unsuited to economical utilization of the plastic film in a form-fill machine where the pouches to be formed have slender spouts extending from wider pouch bodies. Further, available composite dies and techniques for forming seams and cutting along the seam outlines are complex in that they require elaborate operating mechanisms, or they are expensive because of the accuracy needed in making them, or they require heavy presses to operate them, especially where other-than-straight outlines are involved.